Abstract: A method and an integrated device are provided for high-throughput screening of cellular libraries utilizing a droplet microfluidic-based approach. The integrated device comprises 8 or more major functionalities including droplet generation, droplet incubation, droplet reflow, droplet cleaving/generation, droplet synchronization, droplet merging, droplet detection, and droplet sorting for complex screening assays. Integration of each of the droplet functionalities onto a single chip reduces drastic changes in flow experienced at various chip-to-chip interfaces, and the possibility of error.